Adaptive arm support systems and methods for use

ABSTRACT

A system is provided for supporting an arm of a user that includes a harness configured to be worn by the user, and an arm support coupled to the harness and including an arm rest to support an arm of the user. The arm support is configured to accommodate and follow movement of the arm without substantially interfering in such movement. The arm support may at least partially offset a gravitational force acting on the arm as the user moves and the arm support follows the movement of the user&#39;s arm. For example, the arm support may transfer at least a portion of the weight of the user&#39;s arm to the torso or other region of the user&#39;s body and/or may apply an opposing force to at least partially offset the gravitational force acting on the arm.

RELATED APPLICATION DATA

This application is a continuation of application Ser. No. 14/960,243,filed Dec. 4, 2015, issuing as U.S. Pat. No. 10,383,785, which is acontinuation of Ser. No. 13/353,268, filed Jan. 18, 2012, now U.S. Pat.No. 9,205,017, which claims benefit of provisional applications Ser. No.61/433,840, filed Jan. 18, 2011, and 61/507,535, filed Jul. 13, 2011,the entire disclosures of which are expressly incorporated by referenceherein.

FIELD OF THE INVENTION

The present invention relates to systems, devices, and methods forsupporting a user's arms, for example, to adaptive arm support systemsthat support one or both of a user's arms, while allowing substantiallyfree motion, e.g., to allow the user to perform one or more tasks forextended periods of time with one or both arms extended.

BACKGROUND

Numerous tasks require people to work with their arms outstretched.Examples include surgery, dentistry, painting, dishwashing, and productassembly. Persons engaged in such activities may experience fatigue fromprolonged muscular efforts required to resist the force of gravity ontheir arms in order to keep them extended. Weak or disabled persons mayexperience fatigue performing daily tasks. Static arm rests on chairsand work tables are only effective if the task is performed within arelatively restricted area, for example, at a computer keyboard. Tasksthat involve a greater range of motion are not aided by static armrests.

Thus, there is a need for an adaptive armrest or arm support system thatmay relieve fatigue experienced by persons performing tasks involvingmoderate to large ranges of motion.

SUMMARY

The present invention is directed to systems, devices, and methods forsupporting a user's arms, for example, to adaptive arm support systemsor devices that support one or both of a user's arms, while allowingsubstantially free motion, e.g., to allow the user to perform one ormore tasks for extended periods of time with one or both arms extended.

In accordance with one embodiment, an apparatus or system is providedfor supporting an arm of a user that includes a harness configured to beworn on a torso of a user; and an arm support coupled to the harness andconfigured to support a portion of an arm of the user, the arm supportconfigured to accommodate movement of the arm while following themovement without substantially interfering with the movement. The armsupport may be configured to at least partially offset a gravitationalforce acting on the arm as the user moves and the arm support followsthe movement of the user's arm. For example, the arm support maytransfer at least a portion of the weight of the user's arm to the torsoor other region of the user's body and/or may apply an opposing force toat least partially offset the gravitational force acting on the arm.

In one embodiment, the system includes one or more compensation elementscoupled to the arm support to at least partially offset a gravitationalforce acting on the arm as the user moves and the arm support followsthe movement of the user's arm. For example, the compensation element(s)may include one or more springs coupled to the arm support to at leastpartially offset the gravitational force acting on the arm of the useras the user moves without substantially interfering with movement of theuser's arm. Alternatively, the compensation element(s) may include anelectric, hydraulic, or pneumatic system coupled to the arm support toapply forces to the arm support to at least partially offset thegravitational force acting on the arm. In this alternative, thecompensation element(s) may include one or more sensors for detecting anorientation of the arm support to determine a component of gravitationalforce acting on the user's arm, and one or more actuators for applying aforce to at least partially offset the component of gravitational force.

In accordance with another embodiment, an apparatus or system isprovided for supporting an arm of a user that includes a harnessconfigured to be worn on a torso of a user, the harness defining avertical axis extending generally parallel to a spine of the userwearing the harness. An arm support may be coupled to the harness andincluding an arm rest configured to support a portion of an arm of theuser, the support rotatable about a vertical pivot point generallyparallel to the vertical axis and about a horizontal pivot pointgenerally orthogonal to the vertical axis without substantiallyinterfering in movement of the user's arm while the user's arm receivedin the arm rest. One or more compensation elements may be coupled to thearm support to at least partially offset a gravitational force acting onthe arm of the user as the user moves and the arm support follows theuser's movement.

Optionally, a pair of arm supports and associated compensation elementsmay be coupled to the harness for supporting both arms of the user.

In accordance with still another embodiment, a method is provided forsupporting an arm of a user during one or more tasks. A harness may beplaced on the user, the harness comprising an arm support movablerelative to the harness and including an arm rest. A portion of theuser's arm may be supported using the arm rest such that the arm supportsubsequently follows movement of the user's arm. The user may thenperform one or more tasks involving movement of the user's arm, the armsupport at least partially offsetting a gravitational force acting onthe user's arm during the movement without substantially interfering inthe movement.

Thus, the devices, systems, and methods herein may counterbalance all orpart of the weight of one or both of a user's arms as the user performsone or more tasks, which may reduce arm and/or shoulder muscle fatigue.In addition or alternatively, the arm support systems herein mayadaptively reposition with the user, e.g., following movement of theuser's arms as the user performs normal tasks without substantiallyinterfering with the tasks. For example, the weight of one or both ofthe user's arms may be transmitted into the harness via a system of armrests, links, pivots, and/or energy sources, such as springs. Thus, withthe harness worn or otherwise attached to the user, the system maytransmit at least a portion of the weight of the user's arm(s) to theuser's abdomen, shoulder, hips, sides, or other regions of the user'storso, which may be more readily adapted to receive and resist suchforces without undue muscle fatigue and/or discomfort.

Other aspects and features of the present invention will become apparentfrom consideration of the following description taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

It will be appreciated that the exemplary apparatus shown in thedrawings are not necessarily drawn to scale, with emphasis instead beingplaced on illustrating the various aspects and features of theillustrated embodiments.

FIG. 1 is a perspective view of a person with arms outstretched.

FIGS. 2A and 2B show front and rear perspective views, respectively, ofan exemplary embodiment of a body-mounted adaptive arm support systemworn by a user.

FIGS. 3A and 3B show a top view of a body-mountable adaptive arm supportsystem with different arm rotations about a vertical pivot axis. FIGS.4A-4C show side views of a body-mountable adaptive arm support systemwith different arm rotations about a horizontal pivot axis.

FIG. 4D is a detail of the torque element of FIG. 4C.

FIGS. 5A and 5B show front and rear perspective views, respectively, ofthe body-mountable adaptive arm support system of FIGS. 2-4 removed fromthe user.

FIGS. 6A and 6B show front and rear perspective views, respectively, ofan alternative body-mounted adaptive arm support system.

FIGS. 7A and 7B show front and rear views, respectively, of thebody-mountable adaptive arm support system of FIGS. 6A and 6B removedfrom the user.

FIG. 8 shows a front perspective view of another embodiment of abody-mountable adaptive arm support system with alternative torqueelements.

FIG. 9 shows a front perspective view of a body-mountable adaptive armsupport system, similar to that of FIGS. 2-5, with one side disabled.

FIG. 10 shows a rear perspective view of yet another embodiment of abody-mountable adaptive arm support system, similar to that of FIGS. 2-5yet configured for only one arm.

FIG. 11 shows a front perspective view of still another embodiment of abody-mountable adaptive arm support system.

FIGS. 12A and 12B show front perspective views of another embodiment ofa body-mountable adaptive arm support system.

FIGS. 13 and 14 show front perspective views of additional embodimentsof a body-mountable adaptive arm support system.

FIGS. 15A and 15B show front and rear perspective views, respectively,of another embodiment of a body-mountable adaptive arm support systemincluding a mechanism for adjusting a torque element of the system.

FIGS. 16A through 17C show an exemplary embodiment of lock-out, brake,or other safety features that may be provided on any of the supportsystems herein.

FIGS. 18A and 18B show side views of another exemplary embodiment of asupport system include features to facilitate lifting the user's armoverhead.

FIGS. 19A through 22B show various embodiments of features that mayprovide a compensation force for any of the support systems herein.

DETAILED DESCRIPTION

Persons performing tasks with one or both of their arms outstretched forlong periods of time may experience fatigue. As shown in FIG. 1, theforce of gravity Wl and Wr on the outstretched arms 5 of a user U mustbe resisted by the user's shoulder and back muscles M. Over longperiods, this may result in fatigue, and a corresponding degradation inperformance and accuracy. Surgeons, for example, may need to move andhold their arms partially or fully outstretched for long periods oftime. Many report problems with fatigue, tremors, and reduced accuracy.In some cases, surgeons are unable to perform procedures daily, butinstead have to rest for a day between operations. Static armrests, suchas those commonly found on armchairs, provide arm support, but areeffective only in a limited range of positions. Therefore, there is aneed for an arm support system which supports the user's arms over agreater range of motions.

To address this need, the present application provides various adaptivearm support systems that support one or both of a user's arms, e.g.,substantially vertically, while allowing substantially free motion ofthe arm(s), e.g., about multiple axes, to allow the user to perform oneor more tasks for extended periods of time with the arm(s) extended.

As used herein, “vertical” generally means substantially vertical, i.e.,along a vertical axis extending generally parallel to the spinal columnof the user U. Thus, although the user U may generally standsubstantially erect during activities while wearing the adaptive armsupport systems herein, the user U may move in ways to skew the verticalaxis off of true vertical. As used herein, “horizontal” generally meanssubstantially horizontal, i.e., along a horizontal axis that extendsorthogonally, e.g., substantially perpendicular, to the vertical axisextending generally parallel to the spinal column of the user U. For theexample, the horizontal axis may extend generally parallel to an axisextending between the shoulders of the user U.

Turning to the drawings, FIGS. 2A and 2B show a user U wearing a firstexemplary embodiment of an adaptive arm support system 10. Torsobrackets 105, 126 are connected to attachment band 122, and togetherform a harness connected to the abdomen 7 of user U, which may define asubstantially vertical axis aligned with the spine of the user U for thecomponents carried by or otherwise coupled to the torso brackets 105,126.

For example, the attachment band 122 may be secured around the user'swaist, hips, or other region of the user's torso such that the torsobrackets 105, 126 extend from the region to adjacent the user'sshoulder. As shown, the torso brackets 105, 126 may extend generallyparallel to a substantially vertical axis along the spine of the user Uand provide a reference frame relative to which other components of thesystem 10 may move. Alternatively, the torso brackets 105, 126 may beformed from a single rigid member or separate members joined together,e.g., with a coupling portion (not shown) extending along the attachmentband 122 between the lower ends of the brackets 105, 126.

As shown, the torso brackets 105, 126 provide mounting points forshoulder brackets or bars 106, which connect to the torso brackets 105,126 at vertical pivot joints 107. The vertical pivot joints 107 definevertical axes Vr, Vl. Bearings, bushings, and/or other frictionreduction features (not shown) may be employed in vertical pivot joints107, e.g., to provide minimal resistance to movement of the user U, asdescribed further elsewhere herein. Shoulder brackets 106 may rotateabout the vertical pivot joints 107 as shown by arrows 115, 116,providing the user U with the ability to rotate the shoulder brackets106 as desired about vertical axes Vr, Vl.

The shoulder brackets 106 connect to arm brackets or bars 108, 124 athorizontal pivot joints 109, 125. The horizontal pivot joints 109, 125define horizontal axes Hr1, Hl1. The sets of vertical and horizontalaxes Vr, Hr1 and Vl, Hl1 may intersect one another or may be offset butstill generally orthogonal to one another. Bearings, bushings, and/orother friction reduction features (not shown) may also be employed inthe horizontal pivot joints 109, 125, as desired. The arm brackets 108,124 may rotate about the horizontal axes Hr1, Hr2, as shown by arrows114, 117. The arm brackets 108, 124 carry arm rests or pads 120 or otherfeatures at their free ends for supporting the upper arm 5 a of the userU while the forearm 5 b of the user U remains unsupported, as best seenin FIG. 4A. As shown in FIGS. 2A and 2B, the upper arms 5 a of the userU rest in the arm pads 120, which may have a concave shape to enhancesupport of the upper arm 5 a. Optionally, the arm pads 120 may includecushioning elements, e.g., foam, fabric, or other material to provideadditional comfort to the user U. In addition or alternatively, ifdesired straps or other features (not shown) may be provided on the armbrackets 108, 124 and/or arm pads 120 that may be wrapped around thearms 5 or otherwise used to secure the arms 5 relative to the arm pads120.

Torque elements 112 are connected to the shoulder brackets 106 and armbrackets 108, 124, e.g., at the horizontal pivot joints 109, 125, andapply torsional loads 118, 119 to the arm brackets 108, 124, asindicated by the directions of arrows 118, 119. The torsional loads 118,119 may act to counterbalance all, or a portion of, the force of gravityWl, Wr on the arms 5 of the user U. In the embodiment shown, each torqueelement 112 is a spring mechanism, which provides the exclusive energysource for applying an offsetting force (represented by arrows 118, 119)to the arm brackets 108, 124, as described elsewhere herein.

The vertical pivot joints 107 permit shoulder brackets 106 to rotateabout vertical axes Vl, Vr. As shown in FIG. 3A, the shoulder brackets106 generally define horizontal axes Hl1, Hr1. The User U may rotate theshoulder brackets 106 to any desired position consistent with the needsof the task being performed. For example, as shown in FIG. 3B, the userU has moved arm 5 laterally or horizontally, resulting in rotation 130of the shoulder bracket 106, and defining a new horizontal axis Hr2.Thus, there may be infinite positions of the horizontal axes, asdetermined by the motion of the arm(s) 5 of the user U.

The horizontal pivot joints 109, 125 also permit infinite positions ofthe arms 5 of the user U. For example, FIG. 4A shows the user's arm 5 inan essentially horizontal attitude. The force of gravity Wr acts to pullthe user's arm 5 downward. Torsional load 118, applied about horizontalaxis Hr1 by the torque element 112, acts to counterbalance all or aportion of the gravitational force Wr, and reduce the muscular effortthe user U needs to employ to hold the arm 5 outstretched.

FIG. 4B shows the user's arm 5 raised above horizontal along path 134.The torsional load 118 continues to act to at least partiallycounterbalance gravitational force Wr. FIG. 4C shows the user's arm 5lowered below the horizontal along path 136. The torsional load 118 maycontinue to act to at least partially counterbalance gravitational forceWr. Thus, the user U may be able to move their arms 5 to desiredpositions, while the adaptive arm support system 10 moves with (or“adapts to”) the arms 5, simultaneously supporting them withoutsubstantially interfering with the movement.

FIG. 4D is a detail view taken from FIG. 4C, showing an exemplaryembodiment of the torque element 112. As shown, the torque element 112may include a clock spring located at or near horizontal pivot joint125. A pivot shaft 155 is rigidly attached to shoulder bracket 106. Thearm bracket 124 is free to rotate about the pivot shaft 155. As shown, afirst torque element connection feature 158 on the torque element 112may be captured in pivot shaft connection feature 156, and a secondtorque element connection feature 160 on torque element 112 may becaptured behind arm bracket connection feature 164. Thus, the torqueelement 112, coupled to the arm bracket 124 and shoulder bracket 106,may be able to impart a counterbalancing torque 118 to the arm bracket124. Retaining pin 162 holds the torque element 112 in place on thepivot shaft 155. An optional torsional damping element 170 (not shown)may be located in or adjacent to the horizontal pivot joint 125, e.g.,to restrict rotational speed. Optionally, a housing or casing (notshown) may be provided around the torque elements 112, e.g., to protectinternal components and/or provide a desired appearance or finish forthe system 10.

If desired, the torque element(s) 112 may be removable to permit theuser U to adjust the torsional load 118. Optionally, a torque adjustmentmechanism 175 may be located in or adjacent to the horizontal pivotjoint 125, e.g., to permit the user U to adjust the torsional force 118of the torque element 112, as desired. For example, the user U mayprefer a light counterbalancing torque that compensates forapproximately 40% of the gravitational forces Wl, Wr that may act on theuser's arms 5 (under-compensation). In another example, the user U mayprefer a high counterbalancing torque that compensates for approximately115% of the gravitational forces Wl, Wr on the user's arms 5(over-compensation).

FIGS. 5A and 5B show the adaptive arm support system 10 with the user Uomitted merely for clarity. The forces of gravity Wl, Wr on theoutstretched arms 5 of the user U may be transmitted through the armbrackets 108, 124, horizontal pivot joints 109, 125, shoulder brackets106, and vertical pivot joints 107 to the torso brackets 105, 126. Thetorso brackets 105, 126 are, in turn coupled to one or more attachmentbands or other features secured to the user U (one band 122 shown).These three elements make contact with the torso of the user U, e.g., ator around the abdomen 7, and provide a support for transmitting theforces and/or torques input to the adaptive arm support system 10 by theuser's arms 5 to other portions of the user's body. Thus, other portionsof the body may substantially bear the load of the user's arms 5, ratherthan the arms 5 themselves.

Preferably, the areas bearing these loads do not require muscularactivity to do so. For example, reaction forces Rb, Ra, Rw applied bythe user's abdomen 7 by the adaptive arm support system 10 may balancethe load of the user's arms 5. Reaction force Rb, for example, may beapplied to the adaptive arm support system 10 by a force from a portionof the user's back.

The torso brackets 105, 126 may be rigid, semi-rigid, or flexible, ormay have portions of any or all of these. For example, the torsobrackets 105 and 126 may have rigid portions joined to semi-rigidportions. In the embodiment shown, each of the torso brackets 105, 126include a single element that extends substantially parallel to avertical axis defined by the user's spine from a first end attached tothe attachment band 122 to a second end coupled to the vertical pivotjoints 107. Alternatively, the torso brackets 105, 126 may includemultiple elements attached together. For example, a pair of bracketelements may be adjustably coupled together such that the distancebetween the first and second ends, i.e., between the attachment band 122and the vertical pivot joints 107 may be adjusted and fixed, e.g., toaccommodate different height users (not shown).

The attachment band 122 may be rigid, semi-rigid, flexible, or may haveportions of any or all of these. Optionally, the attachment band 122 mayinclude one or more band adjustment features 140, e.g., to provide amechanism for adjusting and fixing attachment band 122, e.g., a buckle,hook and eye fasteners, snaps, laces, and the like (not shown), whichmay facilitate the system 10 being secured around the waist or hips ofthe user U. The first ends of the torso brackets 105, 126 may be fixedrelative to the attachment band 122 or may be adjustable relative to theattachment band 122, for example, laterally along path 150, e.g., usingbuckles, hook and eye fasteners, and the like (not shown). In additionor alternatively, the location of the first ends of the torso brackets105, 126 may also be adjustable vertically relative to the attachmentband 122, e.g., to accommodate different height users. In a furtheralternative, multiple systems may be provided, having differentdimensions, such that a user may select a system best suited to theirbody's size and shape.

Turning to FIGS. 6A and 7B, an alternative embodiment of an adaptive armsupport system 20 is shown that includes many features similar to system10 (with like features including reference numbers increased by 100).Unlike the adaptive arm support system 10, however, the alternativeadaptive arm support system 20 includes torso brackets 205, 226 that areconfigured to extend over the shoulders of the user U and/or that jointhe attachment band(s) 222 at multiple points. Optionally, the system 20may include a band adjustment feature 224, e.g., to provide a mechanismfor adjusting and/or securing the attachment band 222 around the torsoof the user U. Reaction forces Rc, Rs, Rr (shown in FIGS. 7A and 7B),applied by the user's abdomen 7 on the adaptive arm support system 20,may balance the load Wl, Wr of the user's arms 5.

In alternative embodiments, other mounting features may be provided forsecuring the adaptive arm support system 10 or 20 to the torso of a userU, in addition to or instead of the torso brackets and attachment bands,for example, harnesses, backpacks, laces, belts, jackets, and/or othergarments, and the like (not shown). Such mounting systems may supportthe system 10 or 20 at one or more locations, e.g., at the shoulders,around the chest, the waist, hips, and/or other regions of the torso,depending on the degrees of freedom of movement desired by the user. Forexample, a system supported at the shoulders and/or chest may allow theuser U to pivot about their waist easier than a system supported at thewaist or hips.

In further alternative embodiments, other compensation elements may beincluded in the systems 10 or 20 instead of torque elements 112, 212, ifdesired. For example, as shown in FIG. 8, a system 30 is shown that isgenerally similar to the systems 10 or 20, but includes alternativetorque elements 360 at horizontal pivot joints 309, 325. In exemplaryembodiments, the alternative torque elements 360 may be electric,magnetic, pneumatic, hydraulic, and the like. In addition oralternatively, the alternative torque elements 360 may bebattery-powered, self-contained, tethered, attached to external powersources, e.g., by one or more cables (not shown), and the like.

For example, one or more sensors may be provided on the arm support,e.g., sensor 365 shown on arm bracket 308 in FIG. 8, and one or morecontrollers (not shown) may be coupled to the sensor(s) and to one ormore actuators or other compensation elements, in turn, coupled to thearm support. The controller may periodically, intermittently, orsubstantially continuously acquire data from the sensor(s) to determinethe orientation and/or obtain other information regarding the armsupport, and activate the actuator(s) or other compensation element(s)based on the data to apply a force to the arm support to at leastpartially offset the component of gravitational force and/or otherwisetransfer a portion of the weight of the user's arm to the harness and/orother region of the user's body.

For example, in the embodiment in FIG. 8, the torsional loads applied bythe torque elements 360 may be adjustable, for example, by adjustingcurrent to an electric torque element 360 (or, similarly, fluid pressureto a pneumatic or hydraulic torque element, not shown), e.g., using acontroller (not shown) carried on the system or at a nearby location.For example, attitude sensor(s) 365 may be provided, e.g., attached toor otherwise carried by arm brackets 308, that provide position and/orangle feedback to the controller. The controller, in turn, may determinea component of gravitational force acting on the user's arm and activatethe torque element 360 (or other actuators or other compensationelements, not shown) to adjust a counterbalancing torsional load 370,380 generated by the alternative torque elements 360 to suit the user'srequirements. For example, the attitude sensor 365 may signal that theuser's arm is in a certain position, requiring an increase in thecurrent to an electric torque element 360 to increase the opposing forceto enhance support of the arm or, conversely, requiring a decrease inthe current to reduce the opposing force if less support is needed.

Optionally, damping may be provided, e.g., by mechanical, pneumatic,hydraulic, electric elements, and the like. For example, mechanicaldampers, flow controls, electrical controls, and the like (not shown)may be employed, e.g., to restrict rotational speeds.

In some cases, the user U may want to disable all or a portion of any ofthe adaptive arm support systems herein, e.g., systems 10, 20, or 30.FIG. 9 shows an adaptive arm support system 10, similar to that shown inFIGS. 1-5, with the right arm support locked in a back or inactiveposition out of the way of the user's arm 5. Various locking mechanisms(not shown) may be employed, for example, clips, hooks, straps, magnets,threaded fasteners, hook-and-loop fasteners, and the like. Such alock-out feature may be provided for one or both of the arm supports 108of the system 10 of FIG. 9 or for the arm support of a system includingonly a single arm support, such as those described elsewhere herein.

Alternatively, torque elements 360, such as that shown in FIG. 8, mayinclude lock-out features, such as those listed above, which may beactivated, e.g., utilizing electric current, pneumatic pressure,hydraulic pressure, and the like, to direct the arm support to a backposition away from the user's arm 5 such that the user may move the arm5 independent of the system 10. In a further alternative, in the absenceof electric current, pneumatic pressure, hydraulic pressure, and thelike, the user may manually or otherwise control the torque elements 360to direct the arm support to the back or inactive position.

In some cases, the user U may only want a portion of the adaptive armsupport systems described above. For example, FIG. 10 shows an adaptivearm support system 40 that supports only the right arm 5 of the user U.The adaptive arm support system 40 may employ any or all of the featuresof the other adaptive arm support systems described elsewhere herein,such as systems 10, 20, or 30.

Alternative mounting and load transfer arrangements are contemplatedthat may be included in any of the embodiments herein, if desired. Forexample, turning to FIG. 11, a user U is shown wearing an adaptive armsupport system 400 that includes a shoulder harness 404, a pair ofattachment bands 412, 410, and one or more elongate support elements 408(two shown). The shoulder harness 404 may include left and right panels406 formed to fit over or around the user's shoulders, each of which mayhave a torso bracket 416 mounted thereto. The shoulder harness 404 maybe formed from flexible material, such as polymers, leather, compositematerials, and the like, or may be formed from rigid, semi-rigid, and/ormalleable materials, such as metals, plastics, composite materials, andthe like. Similarly, the attachment bands 412, 410 may be formed fromflexible or semi-rigid materials, and/or elastic or inelastic materials,similar to other embodiments herein.

As shown in FIG. 11, the torso bracket 416 is coupled to a shoulderbracket or bar 106 at vertical pivot joint 107, e.g., similar to otherembodiments herein. An arm bracket or bar 108 is coupled to the shoulderbracket 106 at horizontal pivot joint 109, and carries an arm pad 120,also similar to other embodiments herein. Optionally, the verticaland/or horizontal pivot joints 107, 109 may be substantially concentricor otherwise aligned with the user's shoulder joint (not shown), whichmay enhance the arm bracket 108 following movement of the user's arm 5with minimal interference. One or more torque or other compensationelements 112 may be coupled to the shoulder and arm brackets 106, 108,similar to other embodiments herein, e.g., to provide a torsional loadto compensate at least partially for the weight of the user's arm 5.

Also as shown in FIG. 11, a pair of elongate support element(s) 408 areprovided as part of the harness, e.g., connected to the shoulder harness404 at a first or upper end 414, and to the optional waist strap orattachment band 412 at a second or lower end 418. In addition oralternatively, the optional chest strap or attachment band 410 may beprovided, e.g., to enhance securing the left and right forms 406 of theshoulder harness 404 to the user U. Optionally, the elongate supportelement(s) 408 may include springs, rods, cables, and/or othercomponents, which may be formed from elastomeric or polymeric, solid,hollow, pressurized, rigid, semi-rigid, and/or flexible materials. Thesupport element(s) 408 may enhance transmitting the weight of the user'sArm 5 to the waist strap 412, thus distributing the weight over thewaist and hips of the user.

The support element(s) 408 may be substantially straight as shown, ormay be curved, angled, or twisted, as desired to provide desired supportwith minimal discomfort or inconvenience to the user wearing the system400. In addition or alternatively, the support elements 408 may includeone or more telescoping or pivoting elements (not shown). The top and/orbottom junctions 414, 418 may be rigid or may include pivoting joints,similar to other embodiments herein.

Turning to FIGS. 12A and 12B, still another alternate adaptive armsupport system 420 is shown that is generally similar to the system 400shown in FIG. 11. However, the adaptive arm support system includes apair of support elements 422 that are attached to a shoulder harness 415and a waist attachment band 417 by upper and lower pivoting junctions424, 426, which may pivot about axes 430, 431. In addition oralternatively, the support elements 422 may also pivot aboutlongitudinal axes 436, 441. For example, as shown in FIG. 12B, motion ofthe user U bending forward to achieve a task may result in rotation orpivoting of the support elements 422, e.g., to accommodate the user'smotion approximately along path 440. Alternatively, the pivotingjunctions 424, 426 may pivot about axes 430, 431, and the supportelements 422 may pivot about the longitudinal axes 436, 441, e.g., toallow the support elements 422 to bend freely. During such movement, thesupport elements 422 may continue to transmit at least a portion of theweight of the user's Arm 5 to the waist support band 417, although bybending along path 440, the support elements 422 may accommodate bendingmotion of the User U. Alternatively, the support elements 422 may befixedly coupled to one or both of the shoulder harness 415 and theattachment band 417. Optionally, the support element(s) 422 may includeone or more of springs, rods, cables, and the like, may be formed fromelastomeric or polymeric, solid, hollow, pressurized, rigid, semi-rigid,and/or flexible materials, similar to other embodiments herein.

In other embodiments, it may be advantageous to have elements of theadaptive arm support systems herein positioned at different positionsand/or angles relative to the user's shoulder. For example, in FIG. 13,an adaptive arm support system 450 is shown that is generally similar toother embodiments herein. The system 450 includes one or more supportelement 445 (two shown) joined to a shoulder harness 444 at joint 454and joined to a waist support strap 417 at axis mount 446. Alongitudinal axis 448 may be substantially concentric and/or alignedwith the axis mount 446 and the user's shoulder joint. In addition oralternatively, the support element(s) 445 may optionally pivot withinthe axis mount 446, e.g., approximately along path 452.

The axis mount 446 may be mounted at any location around the peripheryof the waist support strap 417 and/or may be appropriately angledrelative to the vertical axis of the system 450. For example, the axismount 446 itself may optionally pivot about pivot axis 449, e.g.,approximately along path 447. The support element(s) 445 may beconstructed similar to other embodiments herein, e.g., includingsprings, rods, cables, and the like, formed from elastomeric orpolymeric, solid, hollow, pressurized, rigid, semi-rigid, and/orflexible materials.

In other embodiments, it may be advantageous to have elements of theadaptive arm support systems not concentric or aligned relative to theuser's shoulder. For example, in FIG. 14, an adaptive arm support system460 is shown that includes support element(s) 458 coupled to a shoulderharness 456 at joint 464 and to a waist support strap 417 at axis mount462. Similar to other embodiments herein, the axis mount 462 may bemounted at any location on the waist support strap 417, and/or may beappropriately angled. For example, the axis mount 462 may define alongitudinal axis 468 that is non-concentric or off-axis with user'sshoulder joint, e.g., such that the axes may intersect or otherwiseextend non-parallel to one another. Optionally, the support element(s)445 may pivot within the axis mount 446, e.g., approximately along path468. The support element(s) 458 may be springs, rods, cables, and thelike, formed from elastomeric or polymeric, solid, hollow, pressurized,rigid, semi-rigid, and/or flexible materials, similar to otherembodiments herein.

Turning to FIGS. 15A and 15B, another embodiment of an adaptive armsupport system 480 is shown that is generally similar to otherembodiments herein, although the system 480 includes only one armsupport. As shown, the adaptive arm support system 480 includes a torsobracket 486 mounted on a shoulder harness 484, a shoulder bracket 492pivotally coupled to the torso bracket 486, and an arm bracket 502pivotally coupled to the shoulder bracket 492, e.g., generally similarto other embodiments herein. Unless the previous embodiments, the system480 includes an adjustment mechanism for adjusting a torque element 500thereon. The torque element 500 may be mounted substantiallyconcentrically with and/or otherwise coupled to a shaft 517, e.g., to atleast partially compensate for the gravitational force acting on the armsupport 502, similar to other embodiments herein.

In the embodiment shown, the adjustment mechanism includes a torqueadjustment knob 514 coupled to a worm screw 516, which is, in turn,coupled to a work gear 518 coupled to the shaft 517. When the torqueadjustment knob 514 is rotated, the worm screw 516 rotates the worm gear518, which consequently rotates the shaft 517 to increases or decreasesthe torque provided by the torque element 500, thereby modifying thecompensation for the user's Arm 5. It will be appreciated that such anadjustment mechanism may be provided on any of the embodiments describedelsewhere herein.

Turning to FIGS. 16A-16H, an adaptive arm support system 480 is shown,similar to that shown in FIGS. 15A and 15B, that includes a lockingmechanism to “lock” the arm bracket 502 and/or other components of thearm support out of the way when the arm bracket 502 is not needed,and/or a safety “brake” to prevent the arm support from movingunexpectedly, which may also be provided on any of the other embodimentsherein. FIGS. 16A through 16H illustrate these features (where, forclarity, the torque element 500 shown in FIGS. 15A and 15B has beenomitted to show features of the locking mechanism). As shown in FIG.16A, the adaptive arm support system 480 includes an arm bracket 502that is coupled at a first end to a pivot block 528 and that carries anarm pad 508 on its second, free end, similar to other embodimentsherein. The pivot block 528 may pivot freely about shaft 517. A safetybar 504 also pivots about the shaft 517.

A spring or other biasing mechanism 526 applies a desired separationforce between the arm bracket 502 and safety bar 504. However, pressurefrom the user's arm 5 on the safety bar 504 may compress the spring 526,and hold the safety bar 504 generally parallel to the arm bracket 502.In this “active” position, the adaptive arm support system 480 is activeand at least partially compensating for the weight of user's Arm 5.

In the active position, a safety pawl 546 (attached to the pivot block528) is in its normal position, with a tip 550 of the safety pawl 546disengaged from safety plate teeth 536 on a safety plate 534 mounted onthe shoulder bracket 492. In this position, the user U may move the arm5 as desired, with a compensation force being provided by the torqueelement 500 (not shown, see FIGS. 15A and 15B). Consequently, similar toother embodiments herein, the arm bracket 502 may rotate about the shaft517 relative to the shoulder bracket 492, and “follow” movement of thearm 5.

If it is desired to disengage the adaptive arm support 480, the user Upushes the arm bracket 502 back into a “lock out” or “'inactive”'position generally along path 560, as shown in FIGS. 16B and 16C (whichshows a back view of the adaptive arm support system 480). The user Umay then rotate the arm bracket 502 generally along path 574, as shownin FIG. 16D, which causes the arm bracket 502 to “hook” on or otherwiseengage a lock-out pin 566 mounted on a hub block 529 on the shoulderbracket 492. Once the arm bracket 502 is “hooked” out of the way onlock-out pin 566, the user U may disengage the arm 5, leaving the armbracket 502 “locked” out of position. FIG. 16E shows a back view of theuser U moving the arm 5 away from locked-out arm bracket 502, while FIG.16F shows this motion from the side.

As the user U moves the arm 5 generally along the path 582, the armbracket 502 is restrained by the lock-out pin 566, and consequentlyremains substantially stationary. The safety bar 504 is then urged awayfrom the arm bracket 502 generally along the path 588 under theinfluence of the spring 526. As the safety bar 504 separates from thearm bracket 502, a cam feature 540 on the safety bar 504 engages thesafety pawl 546 and pushes the safety pawl 546 outwardly generally alongthe path 586. As the safety pawl 546 is pushed outwardly, the safetypawl tip 550 engages the safety plate teeth 536 on the safety plate 534,preventing rotation of the arm bracket 502. Once the user U has “locked”the arm bracket 502 back, the user U may use the arm 5 independently,i.e., without the adaptive arm support 480 following the movement and/orcompensating for the arm's weight (as shown in FIGS. 16G and 16H).

When the user U wishes to re-engage the adaptive arm support system 480,the user U may perform the steps shown in FIGS. 16A through 16H inreverse order, e.g., to reengage the safety bar 502, release the safetypawl 546, and disengage the lock-out pin 566, thereby allowing the armbracket 502 to subsequently support the arm 5.

If the user U accidentally separates the arm 5 from the adaptive armsupport system 480 of FIGS. 15A-15B and/or FIGS. 16A-16H, the system 480may include safety “brake” features to prevent unwanted and/oruncontrolled motion. For example, turning to FIG. 17A, the user U isshown using the adaptive arm support system 480 normally. If the user'sarm 5 slips out of the arm pad 508, as shown in FIG. 17B, the torqueelement 500 may try to urge the arm bracket 502 generally along path 600in an uncontrolled motion. The absence of the user's Arm 5 on the safetybar tab 506 of the safety bar 504 permits the safety bar 504 to separatefrom the arm bracket 502 under the influence of the spring 526,generally along path 602.

As shown in FIG. 16C, however, separation of the safety bar 504 from thearm bracket 502 causes the cam feature 540 on the safety bar 504 toengage the safety pawl 546 and push the safety pawl 546 outwardlygenerally along path 604. As the safety pawl 546 is pushed outwardly,the safety pawl tip 550 may engage the safety plate teeth 536 on thesafety plate 534, as shown in FIG. 17C, thereby preventing unwantedand/or uncontrolled rotation of the arm bracket 502. It will beappreciated that other safety elements may be included in the systemsherein for preventing unwanted and/or uncontrolled motion of the armsupport(s), e.g., based on rotational velocity, including centrifugalclutches, hydraulic dampers, spring-wrap clutches, and the like (notshown).

Optionally, any of the embodiments herein may include one or morefeatures to ease reaching overhead. For example, turning to FIGS. 18Aand 18B, another embodiment of an adaptive arm support system 590 isshown that includes a shoulder bracket 492 and arm bracket 502,generally similar to other embodiments. Unlike the previous embodiments,the system 590 includes an additional pivot joint 596, anchored on astanchion 594, which is mounted or otherwise secured to a shoulderharness 484. In addition, in this embodiment, an extension bracket 592is attached to a torso bracket 486 and is pivotally coupled to thestanchion 594 at the pivot joint 596. The torso bracket 486 may contacta stop feature 597 on the shoulder harness 484, preventing clockwiserotation (from the perspective of FIG. 18A). Thus, when the user's arm 5is moved horizontally or below horizontal, the system 590 may operatesimilar to other embodiments herein.

However, when the user U reaches overhead, as shown in FIG. 18B, theextension bracket 592, coupled to the torso bracket 486 and otherbrackets of the system 590, may pivot generally along path 598, therebyavoiding interference between the user's shoulder and the adaptive armsupport system 590. It will be appreciated that such a configuration maybe provided on any of the embodiments described elsewhere herein.

It will be appreciated that other compensation elements may be includedin any of the embodiments herein, e.g., instead of the torque elements112, 212, 500 described previously, to provide a compensation force toat least partially compensate for the weight of a user's arm 5. Forexample, turning to FIGS. 19A and 19B, another embodiment of an adaptivearm support system 610 is shown that includes a torso brackets 612, 614or other harness (not shown), a shoulder bracket 618 pivotally coupledto the torso bracket 614, and an arm bracket 624 pivotally coupled tothe shoulder bracket 618, similar to other embodiments herein. Inaddition, unlike the previous embodiments, the system 610 includes abiasing mechanism, e.g., an extension spring 632 that may be coupled toor otherwise interact with a set of gears to provide a compensatingforce.

As shown, the shoulder bracket 618 includes an extension bracket 638attached or otherwise fixed thereto, and a sector gear 620 pivotallycoupled thereto by pivot joint 630. Each of the extension bracket 638and the sector gear 620 include a pin or other connector 636, 634,respectively. The extension spring 632 is coupled between the extensionbracket 638 and the sector gear 620, at the pins 636, 634. The sectorgear 620 includes a plurality of teeth 621, which mesh withcorresponding teeth 630 on an arm bracket gear 628 attached to the armbracket 624. As shown in FIG. 19A, as the user U raises the arm 5, thearm bracket 624 follows the movement under the influence of theextension spring 632, generally along path 644, providing a compensatingforce. Simultaneously, the sector gear 620 pivots about the pivot joint622 generally along path 642. Conversely, as shown in FIG. 19B, when theuser U lowers the arm 5, the arm bracket 624 follows generally alongpath 646, as the sector gear 620 pivots about the pivot joint 622,generally along path 648. Although an extension spring 632 is shown, itwill be appreciated that other biasing mechanisms may be providedinstead, such as an air spring, a polymer strap, an elastomer strap, andthe like (not shown).

Turning to FIGS. 20A and 20B, still another embodiment of an adaptivearm support system 660 is shown that includes a compensation element. Inthis embodiment, the system 660 includes a tension element 680 coupledbetween a belt or other harness 686 of the system 660 and an armsupport, e.g., including an arm bracket 672 and arm pad 674 generallysimilar to other embodiments herein. As shown, the tension element 680include a first end attached or otherwise coupled to a belt 686, e.g.,at junction 684. Optional straps 687 are shown that are attached to orotherwise extend from the belt 686, e.g., further secure the belt 686 tothe user U (which may also be included in any of the other embodimentsherein, if desired).

The tension element 680 also includes a second end attached or otherwisecoupled to an extension bracket 678 on the arm bracket 672, e.g., atjunction 682. During use, as the user U raises the arm 5, as shown inFIG. 20A, the arm bracket 672 may follow the movement under theinfluence of the tension element 680, generally along path 688, therebyproviding a compensating force. As the user U lowers the arm 5, as shownin FIG. 20B, the arm bracket 672 may follow generally along path 690,with the tension element 680 providing a compensating force. Inexemplary embodiments, the tension element 680 may be an extensionspring, an elastomer spring, a cable, a strap, a cord, and the like.

Turning to FIGS. 21A and 21B, yet another embodiment of an adaptive armsupport system 700 is shown that includes a compensation rod 704 as acompensation element to provide a compensating force to a user's arm 5.As shown, a first end of the compensation rod 704 is attached to orotherwise coupled to an attachment band or other harness, e.g., to thefront of an abdomen mount 710 at junction 712. A second end of thecompensation rod 704 is coupled to and/or carries an arm pad 706, e.g.,via an optional spherical or other pivotal joint 708. Optionally, thecompensation rod 704 may contact or engage the torso of the user U atother locations, including the shoulder, chest, side, and/or back.

Alternatively, as shown in FIGS. 22A and 22B, an adaptive arm supportsystem 720 may be provided that includes a compensation rod 722 attachedto the back or side of an abdomen mount 710 or other harness, e.g., atjunction 724. Similar to the compensation rod 704, the compensation rod722 may be coupled to or carry an arm pad 706, e.g., via an optionalspherical or other pivotal joint 708. The compensation rod 722 maysupport the user's arm 5, providing a compensating force, and/or mayoptionally contact the user's torso at other locations, including theshoulder, chest, side, and back.

The compensation rods 604, 704 may be formed from flexible or semi-rigidmaterials that may be biased to a predetermined shape or configurationand/or may otherwise provide a compensating force to at least partiallycompensate for the gravitational force acting on the users arm 5 as theuser U performs one or more tasks, similar to other embodiments. It willbe appreciated that the systems described above may be used in a varietyof fields and applications. For example, the systems may be worn byphysicians, e.g., surgeons, dentists, and the like, to facilitateextension of the physician's arm(s) during an extended surgical,medical, or dental procedure. The systems may be worn by constructionworkers, e.g., painters, carpenters, and the like, manufacturingworkers, e.g., involved in product assembly, and the like, disabledindividuals, and/or other users who perform tasks for an extended periodof time in which one or both arms may be extended outwardly from theuser's body.

Generally, the systems herein may be worn or otherwise placed on theuser's body, e.g., by securing a harness onto the user's torso, e.g.,their waist, hips, shoulders, back, chest, and the like. An arm supportof the system, e.g., coupled to or otherwise carried by the harness, maybe used to support the user's arm such that the arm support subsequentlyfollows movement of the user's arm. The user may then perform one ormore tasks involving movement of the user's arm, the arm support atleast partially offsetting a gravitational force acting on the user'sarm and/or at least partially transferring the gravitational force tothe user's torso during the movement without substantially interferingin the movement. Thus, the systems may facilitate the user performingthe task(s) for greater lengths of time and/or with reduced fatigueand/or injury.

It will be appreciated that elements or components shown with anyembodiment herein are merely exemplary for the specific embodiment andmay be used on or in combination with other embodiments disclosedherein.

While the invention is susceptible to various modifications, andalternative forms, specific examples thereof have been shown in thedrawings and are herein described in detail. It should be understood,however, that the invention is not to be limited to the particular formsor methods disclosed, but to the contrary, the invention is to cover allmodifications, equivalents and alternatives falling within the scope ofthe appended claims.

I claim:
 1. A system for supporting an arm of a user, comprising: aharness comprising a belt configured to be worn around a torso of theuser and a shoulder harness configured to be worn over or around one orboth shoulders of the user; an arm support pivotally coupled to theharness and including an arm bracket carrying an arm rest for supportingan upper arm of the user, the arm bracket rotatable vertically about ahorizontal pivot point when the user raises and lowers the arm, the armsupport comprising an extension bracket extending from the pivot pointopposite the arm bracket; and a tension element coupled between theextension bracket and the harness to at least partially offset agravitational force acting on the arm when the user raises and lowersthe arm, wherein the extension bracket is configured to be disposedadjacent the user's back when the harness is worn, and wherein thetension element is configured to extend along the user's back betweenthe extension bracket and the harness when the harness is worn.
 2. Thesystem of claim 1, wherein a first end of the tension element is coupledto the extension bracket and a second end of the tension element iscoupled to the belt.
 3. The system of claim 1, wherein the arm bracketis configured to terminate above the user's elbow.
 4. The system ofclaim 1, wherein the arm support terminates at the arm rest, the armrest configured for receiving a portion of the user's upper arm tosupport the upper arm.
 5. The system of claim 1, wherein the tensionelement comprises one of an extension spring and an elastomer spring. 6.The system of claim 1, wherein the tension element comprises a spring.7. The system of claim 1, wherein the tension element comprises one ofan extension spring, an elastomer spring, a cable, a strap, and a cord.8. A system for supporting an arm of a user, comprising: a harnesscomprising a belt configured to be worn around a torso of the user and ashoulder harness configured to be worn over or around one or bothshoulders of the user; an arm support pivotally coupled to the harnessand including an arm bracket carrying an arm rest for supporting anupper arm of the user, the arm bracket rotatable vertically about ahorizontal pivot point when the user raises and lowers the arm, the armsupport comprising an extension bracket extending from the pivot pointopposite the arm bracket; and a tension element coupled between theextension bracket and the harness to at least partially offset agravitational force acting on the arm when the user raises and lowersthe arm, wherein the extension bracket is configured to rotatevertically downward when the arm bracket is raised as the user raisesthe arm to modify the influence of the compensating force applied by thetension element to at least partially offset a gravitational forceacting on the arm.
 9. A system for supporting an arm of a user,comprising: a harness comprising a belt configured to be worn around atorso of the user and a shoulder harness configured to be worn over oraround one or both shoulders of the user; an arm support pivotallycoupled to the harness and including an arm bracket carrying an arm restfor supporting an upper arm of the user, the arm bracket rotatablevertically about a horizontal pivot point when the user raises andlowers the arm, the arm support comprising an extension bracketextending from the pivot point opposite the arm bracket; and a tensionelement coupled between the extension bracket and the harness to atleast partially offset a gravitational force acting on the arm when theuser raises and lowers the arm, wherein the arm support furthercomprises a shoulder bracket comprising a first end pivotally coupled tothe shoulder harness at a vertical pivot point such that the shoulderbracket is configured to pivot horizontally about a vertical axis, and asecond end coupled to the arm bracket at the horizontal pivot point. 10.A system for supporting an arm of a user, comprising: a harnesscomprising a belt configured to be worn around a torso of the user and ashoulder harness configured to be worn over or around one or bothshoulders of the user; an arm support pivotally coupled to the harnessand including an arm bracket carrying an arm rest for supporting anupper arm of the user, the arm bracket rotatable vertically about ahorizontal pivot point when the user raises and lowers the arm, the armsupport comprising an extension bracket extending from the horizontalpivot point opposite the arm bracket; and a tension element coupled tothe extension bracket to at least partially offset a gravitational forceacting on the arm when the user raises and lowers the arm, wherein theextension bracket is configured to rotate vertically downward when thearm bracket is raised as the user raises the arm to modify the influenceof the compensating force applied by the tension element to at leastpartially offset a gravitational force acting on the arm.
 11. The systemof claim 10, wherein a first end of the tension element is coupled tothe extension bracket and a second end of the tension element is coupledto the belt.
 12. The system of claim 10, wherein the arm bracket isconfigured to terminate above the user's elbow.
 13. The system of claim10, wherein the arm support terminates at the arm rest, the arm restconfigured for receiving a portion of the user's upper arm to supportthe upper arm.
 14. The system of claim 10, wherein the tension elementcomprises one of an extension spring and an elastomer spring.
 15. Asystem for supporting an arm of a user, comprising: a harness comprisinga belt configured to be worn around a torso of the user and a shoulderharness configured to be worn over or around one or both shoulders ofthe user; an arm support pivotally coupled to the harness and includingan arm bracket carrying an arm rest for supporting an upper arm of theuser, the arm bracket rotatable vertically about a horizontal pivotpoint when the user raises and lowers the arm, the arm supportcomprising an extension bracket extending from the horizontal pivotpoint opposite the arm bracket; and a tension element coupled to theextension bracket to at least partially offset a gravitational forceacting on the arm when the user raises and lowers the arm, wherein theextension bracket is configured to be disposed adjacent the user's backwhen the harness is worn, and wherein the tension element is configuredto extend along the user's back between the extension bracket and theharness when the harness is worn.
 16. A system for supporting an arm ofa user, comprising: a harness comprising a belt configured to be wornaround a torso of the user and a shoulder harness configured to be wornover or around one or both shoulders of the user; an arm supportpivotally coupled to the harness and including an arm bracket carryingan arm rest for supporting an upper arm of the user, the arm bracketrotatable vertically about a horizontal pivot point when the user raisesand lowers the arm, the arm support comprising an extension bracketextending from the horizontal pivot point opposite the arm bracket; anda tension element coupled to the extension bracket to at least partiallyoffset a gravitational force acting on the arm when the user raises andlowers the arm, wherein the arm support further comprises a shoulderbracket comprising a first end pivotally coupled to the shoulder harnessat a vertical pivot point such that the shoulder bracket is configuredto pivot horizontally about a vertical axis, and a second end coupled tothe arm bracket at the horizontal pivot point.
 17. A system forsupporting an arm of a user, comprising: a harness comprising a beltconfigured to be worn around a torso of the user and a shoulder harnessconfigured to be worn over or around one or both shoulders of the user;an arm support pivotally coupled to the harness and including an armbracket carrying an arm rest for supporting an upper arm of the user,the arm bracket rotatable about a pivot point configured to be locatedadjacent the user's shoulder when the harness is worn to accommodatewhen the user raises and lowers the arm, the arm support comprising anextension bracket extending from the pivot point opposite the armbracket; and a tension element comprising a first end coupled to theextension bracket and configured to extend vertically adjacent theuser's back when the harness is worn, the tension element configured toat least partially offset a gravitational force acting on the arm whenthe user raises and lowers the arm.
 18. The system of claim 17, whereinthe extension bracket is configured to rotate vertically downward whenthe arm bracket is raised as the user raises the arm to modify theinfluence of the compensating force applied by the tension element to atleast partially offset a gravitational force acting on the arm.